Logo is an educational programming language, designed in 1967 by Wally Feurzeig, Seymour Papert, and

Cynthia Solomon Cynthia Solomon is an American computer scientist known for her work in popularizing computer science for students. She is an innovator in the fields of computer science and educational computing. While working as a researcher at Massachusetts I ...

. The name was coined by Feurzeig while he was at

Bolt, Beranek and Newman Raytheon BBN (originally Bolt, Beranek and Newman, Inc.) is an American research and development company based in Cambridge, Massachusetts. In 1966, the Franklin Institute awarded the firm the Frank P. Brown Medal, in 1999 BBN received the ...

, and derives from the Greek ''logos'', meaning 'word' or 'thought'. A general-purpose language, Logo is widely known for its use of turtle graphics, in which commands for movement and drawing produced line or

vector graphics Vector graphics are a form of computer graphics in which visual images are created directly from geometric shapes defined on a Cartesian plane, such as points, lines, curves and polygons. The associated mechanisms may include vector displ ...

, either on screen or with a small robot termed a

turtle Turtles are reptiles of the order (biology), order Testudines, characterized by a special turtle shell, shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Crypt ...

. The language was conceived to teach concepts of programming related to

Lisp Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized Polish notation#Explanation, prefix notation. Originally specified in the late 1950s, ...

and only later to enable what Papert called " body-syntonic reasoning", where students could understand, predict, and reason about the turtle's motion by imagining what they would do if they were the turtle. There are substantial differences among the many dialects of Logo, and the situation is confused by the regular appearance of turtle graphics programs that are named Logo. Logo is a

multi-paradigm Programming languages can be grouped by the number and types of Programming paradigm, paradigms supported. Paradigm summaries A concise reference for the programming paradigms listed in this article. * Concurrent programming language, Concurrent ...

adaptation and dialect of Lisp, a

functional programming In computer science, functional programming is a programming paradigm where programs are constructed by Function application, applying and Function composition (computer science), composing Function (computer science), functions. It is a declarat ...

language.CSLS Vol 1, Preface .pxvi, Harvey 1997 There is no standard Logo, but UCBLogo has the facilities for handling lists, files, I/O, and

recursion Recursion occurs when the definition of a concept or process depends on a simpler or previous version of itself. Recursion is used in a variety of disciplines ranging from linguistics to logic. The most common application of recursion is in m ...

in scripts, and can be used to teach all computer science concepts, as

UC Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a public land-grant research university in Berkeley, California, United States. Founded in 1868 and named after the Anglo-Irish philosopher George Berkele ...

lecturer Brian Harvey did in his ''Computer Science Logo Style'' trilogy.''Computer Science Logo Style'', Brian Harvey, MIT Press (3 volumes) , , . Availabl
online
Logo is usually an

interpreted language In computer science, an interpreter is a computer program that directly executes instructions written in a programming or scripting language, without requiring them previously to have been compiled into a machine language program. An inter ...

, although compiled Logo dialects (such as Lhogho and Liogo) have been developed. Logo is not case-sensitive but retains the case used for formatting purposes.

History

Logo was created in 1967 at

(BBN), a

Cambridge, Massachusetts Cambridge ( ) is a city in Middlesex County, Massachusetts, United States. It is a suburb in the Greater Boston metropolitan area, located directly across the Charles River from Boston. The city's population as of the 2020 United States census, ...

, research firm, by Wally Feurzeig,

, and Seymour Papert. Its intellectual roots are in

artificial intelligence Artificial intelligence (AI) is the capability of computer, computational systems to perform tasks typically associated with human intelligence, such as learning, reasoning, problem-solving, perception, and decision-making. It is a field of re ...

mathematical logic Mathematical logic is the study of Logic#Formal logic, formal logic within mathematics. Major subareas include model theory, proof theory, set theory, and recursion theory (also known as computability theory). Research in mathematical logic com ...

and

developmental psychology Developmental psychology is the scientific study of how and why humans grow, change, and adapt across the course of their lives. Originally concerned with infants and children, the field has expanded to include adolescence, adult development ...

. For the first four years of Logo research, development and teaching work was done at BBN. The first implementation of Logo, called Ghost, was written in

LISP Lisp (historically LISP, an abbreviation of "list processing") is a family of programming languages with a long history and a distinctive, fully parenthesized Polish notation#Explanation, prefix notation. Originally specified in the late 1950s, ...

on a PDP-1. The goal was to create a mathematical land where children could play with words and sentences. Modeled on LISP, the design goals of Logo included accessible power and informative error messages. The use of virtual Turtles allowed for immediate visual feedback and debugging of graphic programming. The first working Logo turtle robot was created in 1969. A display turtle preceded the physical floor turtle. Modern Logo has not changed very much from the basic concepts predating the first turtle. The first turtle was a tethered floor roamer, not radio-controlled or

wireless Wireless communication (or just wireless, when the context allows) is the transfer of information (''telecommunication'') between two or more points without the use of an electrical conductor, optical fiber or other continuous guided transm ...

. At BBN Paul Wexelblat developed a turtle named Irving that had touch sensors and could move forwards, backwards, rotate, and ding its bell. The earliest year-long school users of Logo were in 1968–69 at Muzzey Jr. High in

Lexington, Massachusetts Lexington is a suburban town in Middlesex County, Massachusetts, United States, located 10 miles (16 km) from Downtown Boston. The population was 34,454 as of the 2020 United States census, 2020 census. The area was originally inhabited by ...

. The virtual and physical turtles were first used by fifth-graders at the Bridge School in the same city in 1970–71.

Turtle and graphics

Logo's most-known feature is the turtle (derived originally from a robot of the same name), an on-screen " cursor" that shows output from commands for movement and small retractable pen, together producing line graphics. It has traditionally been displayed either as a triangle or a turtle icon (though it can be represented by any icon). Turtle graphics were added to the Logo language by Seymour Papert in the late 1960s to support Papert's version of the turtle robot, a simple robot controlled from the user's workstation that is designed to carry out the drawing functions assigned to it using a small retractable pen set into or attached to the robot's body. As a practical matter, the use of turtle geometry instead of a more traditional model mimics the actual movement logic of the turtle robot. The turtle moves with commands that are relative to its own position, ''LEFT 90'' means spin left by 90 degrees. Some Logo implementations, particularly those that allow the use of concurrency and multiple turtles, support collision detection and allow the user to redefine the appearance of the turtle cursor, essentially allowing the Logo turtles to function as sprites. Turtle geometry is also sometimes used in environments other than Logo as an alternative to a strictly coordinate-addressed graphics system. For instance, the idea of turtle graphics is also useful in Lindenmayer system for generating

fractal In mathematics, a fractal is a Shape, geometric shape containing detailed structure at arbitrarily small scales, usually having a fractal dimension strictly exceeding the topological dimension. Many fractals appear similar at various scale ...

Implementations

Some modern derivatives of Logo allow thousands of independently moving turtles. There are two popular implementations:

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a Private university, private research university in Cambridge, Massachusetts, United States. Established in 1861, MIT has played a significant role in the development of many areas of moder ...

's StarLogo and

Northwestern University Northwestern University (NU) is a Private university, private research university in Evanston, Illinois, United States. Established in 1851 to serve the historic Northwest Territory, it is the oldest University charter, chartered university in ...

Center for Connected Learning's (CCL) NetLogo. They allow exploring emergent phenomena and come with many experiments in social studies, biology, physics, and other areas. NetLogo is widely used in agent-based simulation in the biological and social sciences. Although there is no agreed-upon standard, there is a broad consensus on core aspects of the language. In March 2020, there were counted 308 implementations and dialects of Logo, each with its own strengths. Most of those 308 are no longer in wide use, but many are still under development. Commercial implementations widely used in schools include '' MicroWorlds Logo'' and ''Imagine Logo''. Legacy and current implementations include: ; First released in 1980s: * Apple Logo for the

Apple II Plus The Apple II Plus (stylized as Apple ] or apple plus) is the second model of the Apple II series of personal computers produced by Apple Inc., Apple Computer. It was sold from June 1979 to December 1982. Approximately 380,000 II Pluses we ...

and Apple Logo Writer for the Apple IIe, developed by Logo Computer Systems, Inc. (LCSI), were the most broadly used and prevalent early implementations of Logo that peaked in the early to mid-1980s. * Aquarius LOGO was released in 1982 on cartridge by

Mattel Mattel, Inc. ( ) is an American multinational corporation, multinational toy manufacturing and entertainment company headquartered in El Segundo, California. Founded in Los Angeles by Harold Matson and the husband-and-wife duo of Ruth Handler, ...

for the Aquarius home computer. * Atari Logo, developed by LCSI, was released on cartridge by Atari, Inc. in 1983 for the Atari 8-bit computers. * Color Logo was released in 1983 on cartridge (26–2722) and disk (26–2721) by Tandy for the

TRS-80 Color Computer The RadioShack TRS-80 Color Computer, later marketed as the Tandy Color Computer, is a series of home computers developed and sold by Tandy Corporation. Despite sharing a name with the earlier TRS-80, the Color Computer is a completely different ...

. * Commodore Logo was released, with the subtitle "A Language for Learning", by

Commodore International Commodore International Corporation was a home computer and electronics manufacturer with its head office in The Bahamas and its executive office in the United States founded in 1976 by Jack Tramiel and Irving Gould. It was the successor compan ...

. It was based on MIT Logo and enhanced by Terrapin, Inc. The Commodore 64 version (C64105) was released on diskette in 1983; the Plus/4 version (T263001) was released on cartridge in 1984. * SmartLOGO was released on cassette by Coleco for the

ADAM Adam is the name given in Genesis 1–5 to the first human. Adam is the first human-being aware of God, and features as such in various belief systems (including Judaism, Christianity, Gnosticism and Islam). According to Christianity, Adam ...

home computer in 1984. It was developed by LCSI and included a primer, ''Turtle Talk'', by Seymour Papert. * ExperLogo was released in 1985 on diskette by Expertelligence Inc. for the

Macintosh 128K The Macintosh, later rebranded as the Macintosh 128K, is the original Mac (computer), Macintosh personal computer from Apple Inc., Apple. It is the first successful mass-market All-in-one computer, all-in-one desktop personal computer with a gr ...

. * Hot-Logo was released in the mid-1980s by EPCOM for the

MSX MSX is a standardized home computer architecture, announced by ASCII Corporation on June 16, 1983. It was initially conceived by Microsoft as a product for the Eastern sector, and jointly marketed by Kazuhiko Nishi, the director at ASCII Corpo ...

8-bit computers with its own set of commands in Brazilian Portuguese. * TI Logo (for the TI-99/4A computer) was used in primary schools, emphasizing Logo's usefulness in teaching computing fundamentals to novice programmers. * Sprite Logo, also developed by Logo Computer Systems Inc., had ten turtles that could run as independent processes. It ran on Apple II computers, with the aid of a Sprite Card inserted in one of the computer's slots. * IBM marketed their own version of Logo (P/N 6024076), developed jointly by Logo Computer Systems, Inc. (LCSI), for their then-new IBM PC. * ObjectLOGO is a variant of Logo with

object-oriented programming Object-oriented programming (OOP) is a programming paradigm based on the concept of '' objects''. Objects can contain data (called fields, attributes or properties) and have actions they can perform (called procedures or methods and impl ...

extensions and lexical scoping. Version 2.7 was sold by Digitool, Inc. It is no longer being developed or supported, and does not run on versions of the Mac operating system later than 7.5. * Dr. Logo was developed by

Digital Research Digital Research, Inc. (DR or DRI) was a privately held American software company created by Gary Kildall to market and develop his CP/M operating system and related 8-bit, 16-bit and 32-bit systems like MP/M, Concurrent DOS, FlexOS, Multiuser ...

and distributed with computers including the IBM PCjr, Atari ST and the

Amstrad CPC The Amstrad CPC (short for "Colour Personal Computer") is a series of 8-bit home computers produced by Amstrad between 1984 and 1990. It was designed to compete in the mid-1980s home computer market dominated by the Commodore 64 and the ZX Spec ...

. * Acornsoft Logo was released in 1985. It is a commercial implementation of Logo for the 8-bit

BBC Micro The BBC Microcomputer System, or BBC Micro, is a family of microcomputers developed and manufactured by Acorn Computers in the early 1980s as part of the BBC's Computer Literacy Project. Launched in December 1981, it was showcased across severa ...

and Acorn Electron computers. It was developed for Acorn Computers as a full implementation of Logo. It features multiple screen

s and four-channel sound. It was provided on two 16kB ROMs, with utilities and drivers as accompanying software. *Lego Logo is a version of Logo that can manipulate robotic

Lego Lego (, ; ; stylised as LEGO) is a line of plastic construction toys manufactured by the Lego Group, a privately held company based in Billund, Denmark. Lego consists of variously coloured interlocking plastic bricks made of acrylonitri ...

bricks attached to a computer. It was implemented on the

Apple II Apple II ("apple Roman numerals, two", stylized as Apple ][) is a series of microcomputers manufactured by Apple Computer, Inc. from 1977 to 1993. The Apple II (original), original Apple II model, which gave the series its name, was designed ...

and used in American and other grade schools in the late 1980s and early 1990s. Lego Logo is a precursor to Scratch. ; First released in 1990s: * In February 1990, ''Electron User'' published Timothy Grantham's simple implementation of Logo for the Acorn Electron under the article "Talking Turtle". * Comenius Logo is an implementation of Logo developed by Comenius University Faculty of Mathematics and Physics. It started development in December 1991, and is also known in other countries as SuperLogo, MultiLogo and MegaLogo. * UCBLogo, also known as Berkeley Logo, is a free, cross-platform implementation of standard Logo last released in 2009. George Mills at MIT used UCBLogo as the basis for MSWLogo which is more refined and also free. Jim Muller wrote a book, ''The Great Logo Adventure'', which was a complete Logo manual and which used MSWLogo as the demonstration language. MSWLogo has evolved into FMSLogo. ; First released from 2000 onwards: * aUCBLogo is a rewrite and enhancement of UCBLogo. * Imagine Logo is a successor of Comenius Logo, implemented in 2000. The English version was released by Logotron Ltd. in 2001. * LibreLogo is an extension to some versions of LibreOffice. Released in 2012, it is written in Python. It allows vector graphics to be written in Writer. * Logo3D is a tridimensional version of Logo. * POOL is a dialect of Logo with object-oriented extensions, implemented in 2014. POOL programs are compiled and run in the graphical IDE on

Microsoft Windows Windows is a Product lining, product line of Proprietary software, proprietary graphical user interface, graphical operating systems developed and marketed by Microsoft. It is grouped into families and subfamilies that cater to particular sec ...

. A simplified, cross-platform environment is available for systems supporting .NET Framework. * QLogo is an open-source and cross-platform rewrite of UCBLogo with nearly full UCB compatibility that uses hardware-accelerated graphics. * Lynx is an online version of Logo developed by Logo Computer Systems Inc. It can run a large number of turtles, supports animation, parallel processes, colour and collision detection. * LogoMor is an open-source online 3D Logo interpreter based on JavaScript and p5.js. It supports 3D drawings, animations, multimedia, 3D models and various tools. It also includes a fully-featured code editor based on CodeMirror * LbyM is an open-source online Logo interpreter based on JavaScript, created and actively developed (as of 2021) for

Sonoma State University Sonoma State University (SSU, Sonoma State, or Sonoma) is a public university in Sonoma County, California, United States. It is part of the California State University system. Sonoma State offers 92 bachelor's degree programs, 19 master's de ...

's ''Learning by Making'' program. It features traditional Logo programming, connectivity with a customized microcontroller and integration with a modern code editor.

Influence

Logo was a primary influence on the

Smalltalk Smalltalk is a purely object oriented programming language (OOP) that was originally created in the 1970s for educational use, specifically for constructionist learning, but later found use in business. It was created at Xerox PARC by Learni ...

programming language. It is also the main influence on the Etoys educational programming environment and language, which is essentially a Logo variant written in

Squeak Squeak is an object-oriented, class-based, and reflective programming language. It was derived from Smalltalk-80 by a group that included some of Smalltalk-80's original developers, initially at Apple Computer, then at Walt Disney Imaginee ...

(itself a variant of Smalltalk). Logo influenced the procedure/method model in AgentSheets and AgentCubes to program agents similar to the notion of a turtle in Logo. Logo provided the underlying language for Boxer. Boxer was developed at

University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California), is a Public university, public Land-grant university, land-grant research university in Berkeley, California, United States. Founded in 1868 and named after t ...

and MIT and is based on a ''literacy model'', making it easier to use for nontechnical people. KTurtle is a variation of Logo implemented at Qt for the

KDE KDE is an international free software community that develops free and open-source software. As a central development hub, it provides tools and resources that enable collaborative work on its projects. Its products include the KDE Plasma gra ...

environment loosely based on Logo. Two more results of Logo's influence are Kojo, a variant of Scala, and Scratch, a visual, drag-and-drop language which runs in a web browser.

References

External links